Helium Gas Detection Technology
Theory of Helium Gas Detection
The theory behind Helium gas detection is rather simple. Since Helium is lighter than air--it has a molecular weight of 4 and air has a molecular weight of 30--if introduced into an empty pipe with a break in it, the Helium gas molecules will exit from the opening, rise through the subsurface, and exit from the ground at the exact point where the break is.
Gas Leak Detector
We use the MGD-2002 Multi-Gas leak detector, which is manufactured by Dielectric, a subsidiary of the SPX Corp. of Raymond, ME. This instrument, which is composed of a detector unit, hose, and ground probe sensor, is the ideal instrument for detecting leaks in pipes, storage tanks, or any closed system that can be pressurized with the tracer gas.
Pinpointing a Water Leak Using the Helium Gas Detector
An underground water leak can be found with the Helium gas detector using the following 6-step procedure:
1. Mark the Location & Depth of the Water Line
Because the gas survey must be conducted by passing the ground probe sensor across the entire length of the line in question, its location and depth must first be determined.
2. Turn the Water Service Off
The water service is temporarily turned off from a shut-off valve.
3. Drain the Water Out of the Line
An air compressor is used to blow water out of the line.
4. Open & Isolate the Line
The line is shut off at one end and opened up at the other.
5. Pump Helium Gas into the Line
A Helium-Air mixture is pumped into the open end of the line using an air compressor.
6. Conduct a Helium Survey
The ground probe sensor is run across the line to search for the highest concentration of Helium gas.
7. Designate the Location of the Leak
The location with the highest concentration of Helium is marked on the ground with pink paint and/or flags, thereby indicating the location of the underground water leak.
Advantages of Helium Gas Detection Technology
- Can be used in noisy environments.
- Pipe material does not affect results.
- Works about 99% of the time.
- Easy to use, with little ambiguity.
Limitations of Helium Gas Detection Technology
- Water service must be shut off.
- The pipe must be cleared and isolated.
- Helium will not always penetrate reinforced concrete.
- Helium can be deflected by large rocks and bedrock.
- Cannot be used on sleeved pipes.